bhyve hostbridge: Rename "device" property to "devid".

"device" is already used as the generic PCI-level name of the device
model to use (e.g. "hostbridge"). The result was that parsing
"hostbridge" as an integer failed and the host bridge used a device ID
of 0. The EFI ROM asserts that the device ID of the hostbridge is not
0, so booting with the current EFI ROM was failing during the ROM
boot.

Fixes: 621b5090487de9fed1b503769702a9a2a27cc7bb

(cherry picked from commit 9f40a3be3d5dbddf782c3d1eeaadcd022a4dad01)